/*

 * rdrle.c

 *

 * Copyright (C) 1991-1995, Thomas G. Lane.

 * This file is part of the Independent JPEG Group's software.

 * For conditions of distribution and use, see the accompanying README file.

 *

 * This file contains routines to read input images in Utah RLE format.

 * The Utah Raster Toolkit library is required (version 3.1 or later).

 *

 * These routines may need modification for non-Unix environments or

 * specialized applications.  As they stand, they assume input from

 * an ordinary stdio stream.  They further assume that reading begins

 * at the start of the file; start_input may need work if the

 * user interface has already read some data (e.g., to determine that

 * the file is indeed RLE format).

 *

 * Based on code contributed by Mike Lijewski,

 * with updates from Robert Hutchinson.

 */



#include "cdjpeg.h"		/* Common decls for cjpeg/djpeg applications */



#ifdef RLE_SUPPORTED



/* rle.h is provided by the Utah Raster Toolkit. */



#include <rle.h>



/*

 * We assume that JSAMPLE has the same representation as rle_pixel,

 * to wit, "unsigned char".  Hence we can't cope with 12- or 16-bit samples.

 */



#if BITS_IN_JSAMPLE != 8

  Sorry, this code only copes with 8-bit JSAMPLEs. /* deliberate syntax err */

#endif



/*

 * We support the following types of RLE files:

 *   

 *   GRAYSCALE   - 8 bits, no colormap

 *   MAPPEDGRAY  - 8 bits, 1 channel colomap

 *   PSEUDOCOLOR - 8 bits, 3 channel colormap

 *   TRUECOLOR   - 24 bits, 3 channel colormap

 *   DIRECTCOLOR - 24 bits, no colormap

 *

 * For now, we ignore any alpha channel in the image.

 */



typedef enum

  { GRAYSCALE, MAPPEDGRAY, PSEUDOCOLOR, TRUECOLOR, DIRECTCOLOR } rle_kind;





/*

 * Since RLE stores scanlines bottom-to-top, we have to invert the image

 * to conform to JPEG's top-to-bottom order.  To do this, we read the

 * incoming image into a virtual array on the first get_pixel_rows call,

 * then fetch the required row from the virtual array on subsequent calls.

 */



typedef struct _rle_source_struct * rle_source_ptr;



typedef struct _rle_source_struct {

  struct cjpeg_source_struct pub; /* public fields */



  rle_kind visual;              /* actual type of input file */

  jvirt_sarray_ptr image;       /* virtual array to hold the image */

  JDIMENSION row;		/* current row # in the virtual array */

  rle_hdr header;               /* Input file information */

  rle_pixel** rle_row;          /* holds a row returned by rle_getrow() */



} rle_source_struct;





/*

 * Read the file header; return image size and component count.

 */



METHODDEF void

start_input_rle (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)

{

  rle_source_ptr source = (rle_source_ptr) sinfo;

  JDIMENSION width, height;

#ifdef PROGRESS_REPORT

  cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;

#endif



  /* Use RLE library routine to get the header info */

  source->header = *rle_hdr_init(NULL);

  source->header.rle_file = source->pub.input_file;

  switch (rle_get_setup(&(source->header))) {

  case RLE_SUCCESS:

    /* A-OK */

    break;

  case RLE_NOT_RLE:

    ERREXIT(cinfo, JERR_RLE_NOT);

    break;

  case RLE_NO_SPACE:

    ERREXIT(cinfo, JERR_RLE_MEM);

    break;

  case RLE_EMPTY:

    ERREXIT(cinfo, JERR_RLE_EMPTY);

    break;

  case RLE_EOF:

    ERREXIT(cinfo, JERR_RLE_EOF);

    break;

  default:

    ERREXIT(cinfo, JERR_RLE_BADERROR);

    break;

  }



  /* Figure out what we have, set private vars and return values accordingly */

  

  width  = source->header.xmax - source->header.xmin + 1;

  height = source->header.ymax - source->header.ymin + 1;

  source->header.xmin = 0;		/* realign horizontally */

  source->header.xmax = width-1;



  cinfo->image_width      = width;

  cinfo->image_height     = height;

  cinfo->data_precision   = 8;  /* we can only handle 8 bit data */



  if (source->header.ncolors == 1 && source->header.ncmap == 0) {

    source->visual     = GRAYSCALE;

    TRACEMS2(cinfo, 1, JTRC_RLE_GRAY, width, height);

  } else if (source->header.ncolors == 1 && source->header.ncmap == 1) {

    source->visual     = MAPPEDGRAY;

    TRACEMS3(cinfo, 1, JTRC_RLE_MAPGRAY, width, height,

             1 << source->header.cmaplen);

  } else if (source->header.ncolors == 1 && source->header.ncmap == 3) {

    source->visual     = PSEUDOCOLOR;

    TRACEMS3(cinfo, 1, JTRC_RLE_MAPPED, width, height,

	     1 << source->header.cmaplen);

  } else if (source->header.ncolors == 3 && source->header.ncmap == 3) {

    source->visual     = TRUECOLOR;

    TRACEMS3(cinfo, 1, JTRC_RLE_FULLMAP, width, height,

	     1 << source->header.cmaplen);

  } else if (source->header.ncolors == 3 && source->header.ncmap == 0) {

    source->visual     = DIRECTCOLOR;

    TRACEMS2(cinfo, 1, JTRC_RLE, width, height);

  } else

    ERREXIT(cinfo, JERR_RLE_UNSUPPORTED);

  

  if (source->visual == GRAYSCALE || source->visual == MAPPEDGRAY) {

    cinfo->in_color_space   = JCS_GRAYSCALE;

    cinfo->input_components = 1;

  } else {

    cinfo->in_color_space   = JCS_RGB;

    cinfo->input_components = 3;

  }



  /*

   * A place to hold each scanline while it's converted.

   * (GRAYSCALE scanlines don't need converting)

   */

  if (source->visual != GRAYSCALE) {

    source->rle_row = (rle_pixel**) (*cinfo->mem->alloc_sarray)

      ((j_common_ptr) cinfo, JPOOL_IMAGE,

       (JDIMENSION) width, (JDIMENSION) cinfo->input_components);

  }



  /* request a virtual array to hold the image */

  source->image = (*cinfo->mem->request_virt_sarray)

    ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,

     (JDIMENSION) (width * source->header.ncolors),

     (JDIMENSION) height, (JDIMENSION) 1);



#ifdef PROGRESS_REPORT

  if (progress != NULL) {

    /* count file input as separate pass */

    progress->total_extra_passes++;

  }

#endif



  source->pub.buffer_height = 1;

}





/*

 * Read one row of pixels.

 * Called only after load_image has read the image into the virtual array.

 * Used for GRAYSCALE, MAPPEDGRAY, TRUECOLOR, and DIRECTCOLOR images.

 */



METHODDEF JDIMENSION

get_rle_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)

{

  rle_source_ptr source = (rle_source_ptr) sinfo;



  source->row--;

  source->pub.buffer = (*cinfo->mem->access_virt_sarray)

    ((j_common_ptr) cinfo, source->image, source->row, (JDIMENSION) 1, FALSE);



  return 1;

}



/*

 * Read one row of pixels.

 * Called only after load_image has read the image into the virtual array.

 * Used for PSEUDOCOLOR images.

 */



METHODDEF JDIMENSION

get_pseudocolor_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)

{

  rle_source_ptr source = (rle_source_ptr) sinfo;

  JSAMPROW src_row, dest_row;

  JDIMENSION col;

  rle_map *colormap;

  int val;



  colormap = source->header.cmap;

  dest_row = source->pub.buffer[0];

  source->row--;

  src_row = * (*cinfo->mem->access_virt_sarray)

    ((j_common_ptr) cinfo, source->image, source->row, (JDIMENSION) 1, FALSE);



  for (col = cinfo->image_width; col > 0; col--) {

    val = GETJSAMPLE(*src_row++);

    *dest_row++ = (JSAMPLE) (colormap[val      ] >> 8);

    *dest_row++ = (JSAMPLE) (colormap[val + 256] >> 8);

    *dest_row++ = (JSAMPLE) (colormap[val + 512] >> 8);

  }



  return 1;

}





/*

 * Load the image into a virtual array.  We have to do this because RLE

 * files start at the lower left while the JPEG standard has them starting

 * in the upper left.  This is called the first time we want to get a row

 * of input.  What we do is load the RLE data into the array and then call

 * the appropriate routine to read one row from the array.  Before returning,

 * we set source->pub.get_pixel_rows so that subsequent calls go straight to

 * the appropriate row-reading routine.

 */



METHODDEF JDIMENSION

load_image (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)

{

  rle_source_ptr source = (rle_source_ptr) sinfo;

  JDIMENSION row, col;

  JSAMPROW  scanline, red_ptr, green_ptr, blue_ptr;

  rle_pixel **rle_row;

  rle_map *colormap;

  char channel;

#ifdef PROGRESS_REPORT

  cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;

#endif



  colormap = source->header.cmap;

  rle_row = source->rle_row;



  /* Read the RLE data into our virtual array.

   * We assume here that (a) rle_pixel is represented the same as JSAMPLE,

   * and (b) we are not on a machine where FAR pointers differ from regular.

   */

  RLE_CLR_BIT(source->header, RLE_ALPHA); /* don't read the alpha channel */



#ifdef PROGRESS_REPORT

  if (progress != NULL) {

    progress->pub.pass_limit = cinfo->image_height;

    progress->pub.pass_counter = 0;

    (*progress->pub.progress_monitor) ((j_common_ptr) cinfo);

  }

#endif



  switch (source->visual) {



  case GRAYSCALE:

  case PSEUDOCOLOR:

    for (row = 0; row < cinfo->image_height; row++) {

      rle_row = (rle_pixel **) (*cinfo->mem->access_virt_sarray)

         ((j_common_ptr) cinfo, source->image, row, (JDIMENSION) 1, TRUE);

      rle_getrow(&source->header, rle_row);

#ifdef PROGRESS_REPORT

      if (progress != NULL) {

        progress->pub.pass_counter++;

        (*progress->pub.progress_monitor) ((j_common_ptr) cinfo);

      }

#endif

    }

    break;



  case MAPPEDGRAY:

  case TRUECOLOR:

    for (row = 0; row < cinfo->image_height; row++) {

      scanline = * (*cinfo->mem->access_virt_sarray)

        ((j_common_ptr) cinfo, source->image, row, (JDIMENSION) 1, TRUE);

      rle_row = source->rle_row;

      rle_getrow(&source->header, rle_row);



      for (col = 0; col < cinfo->image_width; col++) {

        for (channel = 0; channel < source->header.ncolors; channel++) {

          *scanline++ = (JSAMPLE)

            (colormap[GETJSAMPLE(rle_row[channel][col]) + 256 * channel] >> 8);

        }

      }



#ifdef PROGRESS_REPORT

      if (progress != NULL) {

        progress->pub.pass_counter++;

        (*progress->pub.progress_monitor) ((j_common_ptr) cinfo);

      }

#endif

    }

    break;



  case DIRECTCOLOR:

    for (row = 0; row < cinfo->image_height; row++) {

      scanline = * (*cinfo->mem->access_virt_sarray)

        ((j_common_ptr) cinfo, source->image, row, (JDIMENSION) 1, TRUE);

      rle_getrow(&source->header, rle_row);



      red_ptr   = rle_row[0];

      green_ptr = rle_row[1];

      blue_ptr  = rle_row[2];



      for (col = cinfo->image_width; col > 0; col--) {

        *scanline++ = *red_ptr++;

        *scanline++ = *green_ptr++;

        *scanline++ = *blue_ptr++;

      }



#ifdef PROGRESS_REPORT

      if (progress != NULL) {

        progress->pub.pass_counter++;

        (*progress->pub.progress_monitor) ((j_common_ptr) cinfo);

      }

#endif

    }

  }



#ifdef PROGRESS_REPORT

  if (progress != NULL)

    progress->completed_extra_passes++;

#endif



  /* Set up to call proper row-extraction routine in future */

  if (source->visual == PSEUDOCOLOR) {

    source->pub.buffer = source->rle_row;

    source->pub.get_pixel_rows = get_pseudocolor_row;

  } else {

    source->pub.get_pixel_rows = get_rle_row;

  }

  source->row = cinfo->image_height;



  /* And fetch the topmost (bottommost) row */

  return (*source->pub.get_pixel_rows) (cinfo, sinfo);   

}





/*

 * Finish up at the end of the file.

 */



METHODDEF void

finish_input_rle (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)

{

  /* no work */

}





/*

 * The module selection routine for RLE format input.

 */



GLOBAL cjpeg_source_ptr

jinit_read_rle (j_compress_ptr cinfo)

{

  rle_source_ptr source;



  /* Create module interface object */

  source = (rle_source_ptr)

      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,

                                  SIZEOF(rle_source_struct));

  /* Fill in method ptrs */

  source->pub.start_input = start_input_rle;

  source->pub.finish_input = finish_input_rle;

  source->pub.get_pixel_rows = load_image;



  return (cjpeg_source_ptr) source;

}



#endif /* RLE_SUPPORTED */

